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Red meat has been an important part of the human diet throughout human evolution. When included as part of a healthy, varied diet, red meat provides a rich source of high biological value protein and essential nutrients, some of which are more bioavailable than in alternative food sources. Particular nutrients in red meat have been identified as being in short supply in the diets of some groups of the population. The present paper discusses the role of red meat in the diets of young infants, adolescents, women of childbearing age and older adults and highlights key nutrients red meat can provide for these groups. The role of red meat in relation to satiety and weight control is discussed as the inclusion of lean red meat in a healthy, varied diet may help weight loss as part of an energy-reduced diet. A summary of the UK advice on the amount of red meat that can be consumed as part of a healthy, varied diet is also provided.

Meat is a food rich in protein, minerals such as iron and zinc as well as a variety of vitamins, in particular B vitamins. However, the content of cholesterol and saturated fat is higher than in some other food groups. Processed meat is defined as products usually made of red meat that are cured, salted or smoked (e.g. ham or bacon) in order to improve the durability of the food and/or to improve colour and taste, and often contain a high amount of minced fatty tissue (e.g. sausages). Hence, high consumption of processed foods may lead to an increased intake of saturated fats, cholesterol, salt, nitrite, haem iron, polycyclic aromatic hydrocarbons, and, depending upon the chosen food preparation method, also heterocyclic amines. Several large cohort studies have shown that a high consumption of processed (red) meat is related to increased overall and cause-specific mortality. A meta-analysis of nine cohort studies observed a higher mortality among high consumers of processed red meat (relative risk (RR) = 1·23; 95 % CI 1·17, 1·28, top v. bottom consumption category), but not unprocessed red meat (RR = 1·10; 95 % CI 0·98, 1·22). Similar associations were reported in a second meta-analysis. All studies argue that plausible mechanisms are available linking processed meat consumption and risk of chronic diseases such as CVD, diabetes mellitus or some types of cancer. However, the results of meta-analyses do show some degree of heterogeneity between studies, and it has to be taken into account that individuals with low red or processed meat consumption tend to have a healthier lifestyle in general. Hence, substantial residual confounding cannot be excluded. Information from other types of studies in man is needed to support a causal role of processed meat in the aetiology of chronic diseases, e.g. studies using the Mendelian randomisation approach.

Selective breeding and improved nutritional management over the past 20–30 years has resulted in dramatic improvements in growth efficiency for pigs and poultry, particularly lean tissue growth. However, this has been achieved using high-quality feed ingredients, such as wheat and soya that are also used for human consumption and more recently biofuels production. Ruminants on the other hand are less efficient, but are normally fed poorer quality ingredients that cannot be digested by human subjects, such as grass or silage. The challenges therefore are to: (i) maintain the current efficiency of growth of pigs and poultry, but using more ingredients not needed to feed the increasing human population or for the production of biofuels; (ii) improve the efficiency of growth in ruminants; (iii) at the same time produce animal products (meat, milk and eggs) of equal or improved quality. This review will describe the use of: (a) enzyme additives for animal feeds, to improve feed digestibility; (b) known growth promoting agents, such as growth hormone, β-agonists and anabolic steroids, currently banned in the European Union but used in other parts of the world; (c) recent transcriptomic studies into molecular mechanisms for improved growth efficiency via low residual feed intake. In doing so, the use of genetic manipulation in animals will also be discussed.

CVD are the leading cause of mortality and morbidity worldwide. One of the key dietary recommendations for CVD prevention is reduction of saturated fat intake. Yet, despite milk and dairy foods contributing on average 27 % of saturated fat intake in the UK diet, evidence from prospective cohort studies does not support a detrimental effect of milk and dairy foods on risk of CVD. The present paper provides a brief overview of the role of milk and dairy products in the diets of UK adults, and will summarise the evidence in relation to the effects of milk and dairy consumption on CVD risk factors and mortality. The majority of prospective studies and meta-analyses examining the relationship between milk and dairy product consumption and risk of CVD show that milk and dairy products, excluding butter, are not associated with detrimental effects on CVD mortality or risk biomarkers that include serum LDL-cholesterol. In addition, there is increasing evidence that milk and dairy products are associated with lower blood pressure and arterial stiffness. These apparent benefits of milk and dairy foods have been attributed to their unique nutritional composition, and suggest that the elimination of milk and dairy may not be the optimum strategy for CVD risk reduction.

Symposium 2: Milk and eggs, health and sustainability

Eggs have one of the lowest energy to nutrient density ratios of any food, and contain a quality of protein that is superior to beef steak and similar to dairy. From a nutritional perspective, this must qualify eggs as ‘good’. The greater burden of proof has been to establish that eggs are not ‘bad’, by increasing awareness of the difference between dietary and blood cholesterol, and accumulating sufficient evidence to exonerate eggs from their associations with CVD and diabetes. After 60 years of research, a general consensus has now been reached that dietary cholesterol, chiefly from eggs, exerts a relatively small effect on serum LDL-cholesterol and CVD risk, in comparison with other diet and lifestyle factors. While dietary guidelines have been revised worldwide to reflect this view, associations between egg intake and the incidence of diabetes, and increased CVD risk in diabetes, prevail. These associations may be explained, in part, by residual confounding produced by other dietary components. The strength of evidence that links egg intake to increased CVD risk in diabetes is also complicated by variation in the response of serum LDL-cholesterol to eggs and dietary cholesterol in types 1 and 2 diabetes. On balance, the answer to the question as to whether eggs are ‘bad’, is probably ‘no’, but we do need to gain a better understanding of the effects of dietary cholesterol and its association with CVD risk in diabetes.

The review presents results of recent life cycle assessment studies aiming to quantify and improve the environmental performance of UK poultry production systems, including broiler meat, egg and turkey meat production. Although poultry production has been found to be relatively environmentally friendly compared with the production of other livestock commodities, it still contributes to environmental impacts, such as global warming, eutrophication and acidification. Amongst different sub-processes, feed production and transport contributes about 70 % to the global warming potential of poultry systems, whereas manure management contributes about 40–60 % to their eutrophication potential and acidification potential, respectively. All these impacts can be reduced by improving the feed efficiency, either by changing the birds through genetic selection or by making the feed more digestible (e.g. by using additives such as enzymes). However, although genetic selection has the potential to reduce the resources needed for broiler production (including feed consumption), the changing need of certain feed ingredients, most notably protein sources as a result of changes in bird requirements may limit the benefits of this strategy. The use of alternative feed ingredients, such as locally grown protein crops and agricultural by-products, as a replacement of South American grown soya, can potentially also lead to improvements in several environmental impact categories, as long as such feeding strategies have no negative effect on bird performance. Other management options, such as improving poultry housing and new strategies for manure management have also the potential to further improve the environmental sustainability of the poultry industries in Europe.

The status and potential of aquaculture is considered as part of a broader food landscape of wild aquatic and terrestrial food sources. The rationale and resource base required for the development of aquaculture are considered in the context of broader societal development, cultural preferences and human needs. Attention is drawn to the uneven development and current importance of aquaculture globally as well as its considerable heterogeneity of form and function compared with established terrestrial livestock production. The recent drivers of growth in demand and production are examined and the persistent linkages between exploitation of wild stocks, full life cycle culture and the various intermediate forms explored. An emergent trend for sourcing aquaculture feeds from alternatives to marine ingredients is described and the implications for the sector with rapidly growing feed needs discussed. The rise of non-conventional and innovative feed ingredients, often shared with terrestrial livestock, are considered, including aquaculture itself becoming a major source of marine ingredients. The implications for the continued expected growth of aquaculture are set in the context of sustainable intensification, with the challenges that conventional intensification and emergent integration within, and between, value chains explored. The review concludes with a consideration of the implications for dependent livelihoods and projections for various futures based on limited resources but growing demand.

Vegetarians, who do not eat any meat, poultry or fish, constitute a significant minority of the world's population. Lacto-ovo-vegetarians consume dairy products and/or eggs, whereas vegans do not eat any foods derived wholly or partly from animals. Concerns over the health, environmental and economic consequences of a diet rich in meat and other animal products have focussed attention on those who exclude some or all of these foods from their diet. There has been extensive research into the nutritional adequacy of vegetarian diets, but less is known about the long-term health of vegetarians and vegans. We summarise the main findings from large cross-sectional and prospective cohort studies in western countries with a high proportion of vegetarian participants. Vegetarians have a lower prevalence of overweight and obesity and a lower risk of IHD compared with non-vegetarians from a similar background, whereas the data are equivocal for stroke. For cancer, there is some evidence that the risk for all cancer sites combined is slightly lower in vegetarians than in non-vegetarians, but findings for individual cancer sites are inconclusive. Vegetarians have also been found to have lower risks for diabetes, diverticular disease and eye cataract. Overall mortality is similar for vegetarians and comparable non-vegetarians, but vegetarian groups compare favourably with the general population. The long-term health of vegetarians appears to be generally good, and for some diseases and medical conditions it may be better than that of comparable omnivores. Much more research is needed, particularly on the long-term health of vegans.

Boyd Orr Lecture

The global increase in demand for meat and the limited land area available prompt the search for alternative protein sources. Also the sustainability of meat production has been questioned. Edible insects as an alternative protein source for human food and animal feed are interesting in terms of low greenhouse gas emissions, high feed conversion efficiency, low land use, and their ability to transform low value organic side streams into high value protein products. More than 2000 insect species are eaten mainly in tropical regions. The role of edible insects in the livelihoods and nutrition of people in tropical countries is discussed, but this food source is threatened. In the Western world, there is an increasing interest in edible insects, and examples are given. Insects as feed, in particular as aquafeed, have a large potential. Edible insects have about the same protein content as conventional meat and more PUFA. They may also have some beneficial health effects. Edible insects need to be processed and turned into palatable dishes. Food safety may be affected by toxicity of insects, contamination with pathogens, spoilage during conservation and allergies. Consumer attitude is a major issue in the Western world and a number of strategies are proposed to encourage insect consumption. We discuss research pathways to make insects a viable sector in food and agriculture: an appropriate disciplinary focus, quantifying its importance, comparing its nutritional value to conventional protein sources, environmental benefits, safeguarding food safety, optimising farming, consumer acceptance and gastronomy.

Irritable bowel syndrome (IBS) is a functional bowel disorder characterised by abdominal pain or discomfort with disordered defecation. This review describes the role of the gastrointestinal (GI) microbiota in the pathogenesis of IBS and how dietary strategies to manage symptoms impact on the microbial community. Evidence suggests a dysbiosis of the luminal and mucosal colonic microbiota in IBS, frequently characterised by a reduction in species of Bifidobacteria which has been associated with worse symptom profile. Probiotic supplementation trials suggest intentional modulation of the GI microbiota may be effective in treating IBS. A smaller number of prebiotic supplementation studies have also demonstrated effectiveness in IBS whilst increasing Bifidobacteria. In contrast, a novel method of managing IBS symptoms is the restriction of short-chain fermentable carbohydrates (low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet). Studies consistently demonstrate clinical effectiveness of the low FODMAP diet in patients with IBS. However, one unintentional consequence of this dietary intervention is its impact on the microbiota. This leads to an interesting paradox; namely, increasing luminal Bifidobacteria through probiotic supplementation is associated with a reduction in IBS symptoms while in direct conflict to this, the low FODMAP diet has clinical efficacy but markedly reduces luminal Bifidobacteria concentration. Given the multifactorial aetiology of IBS, the heterogeneity of symptoms and the complex and diverse nature of the microbiome, it is probable that both interventions are effective in patient subgroups. However combination treatment has never been explored and as such, presents an exciting opportunity for optimising clinical management, whilst preventing potentially deleterious effects on the GI microbiota.

The belief that breakfast is the most important meal of day has been derived from cross-sectional studies that have associated breakfast consumption with a lower BMI. This suggests that breakfast omission either leads to an increase in energy intake or a reduction in energy expenditure over the remainder of the day, resulting in a state of positive energy balance. However, observational studies do not imply causality. A number of intervention studies have been conducted, enabling more precise determination of breakfast manipulation on indices of energy balance. This review will examine the results from these studies in adults, attempting to identify causal links between breakfast and energy balance, as well as determining whether consumption of breakfast influences exercise performance. Despite the associations in the literature, intervention studies have generally found a reduction in total daily energy intake when breakfast is omitted from the daily meal pattern. Moreover, whilst consumption of breakfast supresses appetite during the morning, this effect appears to be transient as the first meal consumed after breakfast seems to offset appetite to a similar extent, independent of breakfast. Whether breakfast affects energy expenditure is less clear. Whilst breakfast does not seem to affect basal metabolism, breakfast omission may reduce free-living physical activity and endurance exercise performance throughout the day. In conclusion, the available research suggests breakfast omission may influence energy expenditure more strongly than energy intake. Longer term intervention studies are required to confirm this relationship, and determine the impact of these variables on weight management.

The prevalence of cardiometabolic diseases is a significant public health burden worldwide. Emerging evidence supports the inverse association between greater dairy consumption and reduced risk of cardiometabolic diseases. Dairy proteins may have an important role in the favourable impact of dairy on human health such as blood pressure (BP), blood lipid and glucose control. The purpose of this review is to update and critically evaluate the evidence on the impacts of casein and whey protein in relation to metabolic function. Evidence from short-term clinical studies assessing postprandial responses to milk protein ingestion suggests benefits on vascular function independent of BP, as well as improvement in glycaemic homeostasis. Long-term interventions have been less conclusive, with some showing benefits and others indicating a lack of improvement in vascular function. During chronic consumption BP appears to be lowered and both dyslipidaemia and hyperglacaemia seem to be controlled. Limited number of trials investigated the effects of dairy proteins on oxidative stress and inflammation. Although the underlying mechanisms of milk proteins on cardiometabolic homeostasis remains to be elucidated, the most likely mechanism is to improve insulin resistance. The incorporation of meals enriched with dairy protein in the habitual diet may result in the beneficial effects on cardiometabolic health. Nevertheless, future well-designed, controlled studies are needed to investigate the relative effects of both casein and whey protein on BP, vascular function, glucose homeostasis and inflammation.

The prevalence of type 2 diabetes (T2D) is predicted to reach unprecedented levels in the next few decades. In addition to excess body weight, there may be other overlapping dietary drivers of impaired glucose homeostasis that are associated with an obesogenic diet, such as regular exposure to postprandial spikes in blood glucose arising from diets dominated by highly refined starches and added sugars. Strategies to reduce postprandial hyperglycaemia by optimising the functionality of foods would strengthen efforts to reduce the risk of T2D. Berry bioactives, including anthocyanins, are recognised for their inhibitory effects on carbohydrate digestion and glucose absorption. Regular consumption of berries has been associated with a reduction in the risk of T2D. This review aims to examine the evidence from in vitro, animal and human studies, showing that berries and berry anthocyanins may act in the gut to modulate postprandial glycaemia. Specifically, berry extracts and anthocyanins inhibit the activities of pancreatic α-amylase and α-glucosidase in the gut lumen, and interact with intestinal sugar transporters, sodium-dependent glucose transporter 1 and GLUT2, to reduce the rate of glucose uptake into the circulation. Growing evidence from randomised controlled trials suggests that berry extracts, purées and nectars acutely inhibit postprandial glycaemia and insulinaemia following oral carbohydrate loads. Evidence to date presents a sound basis for exploring the potential for using berries/berry extracts as an additional stratagem to weight loss, adherence to dietary guidelines and increasing physical exercise, for the prevention of T2D.

The seriousness and scale of the physical, psychological, economic and societal consequences relating to poor diets, inactivity and obesity is unprecedented. Consequently, the contextual factors underpinning the work of a nutritionist in the civil service are complex and significant; however, there are real opportunities to make a difference and help improve the health of the nation. The present paper describes the delivery of public health nutrition through two work programmes, namely action to support young people develop healthier lifestyle choices and more recently the investigation and deployment of local insights to develop action to tackle obesity. Combining the application of nutrition expertise along with broader skills and approaches has enabled the translation of research and evidence into programmes of work to better the public's health. It is evident that the appropriate evaluation of such approaches has helped to deliver engaging and practical learning opportunities for young people. Furthermore, efforts to build on local intelligence and seek collaborative development can help inform the evidence base and seek to deliver public health approaches, which resonate with how people live their lives.

Red and processed meat (RPM) intake varies widely globally. In some high-income countries (HIC) the last decade has witnessed an overall decline or stabilisation in the consumption of RPM, in contrast to emerging economies where its consumption continues to increase with rising income and rapid urbanisation. The production and consumption of RPM have become major concerns regarding the environmental impacts of livestock in particular, but also because of associations between high RPM consumption and diet-related non-communicable disease. Therefore, it is important to identify socioeconomic and demographic drivers of the consumption of RPM. This paper explores how consumption of RPM differs with age, gender, socioeconomic status and in different global contexts. There are some key socioeconomic and demographic patterns in RPM consumption. Men tend to consume RPM more often and in higher quantities, and there is evidence of a social gradient in HIC, with lower socioeconomic groups consuming RPM more often and in larger quantities. Patterns for consumption with age are less clear cut. It is apparent that consumers in HIC are still consuming high levels of RPM, although the downward shifts in some socioeconomic and demographic groups is encouraging and suggests that strategies could be developed to engage those consumers identified as high RPM consumers. In low- and middle-income countries, RPM consumption is rising, especially in China and Brazil, and in urban areas. Ways of encouraging populations to maintain their traditional healthy eating patterns need to be found in low- and middle-income countries, which will have health, environmental and economic co-benefits.

Over a few decades, Korean diet has changed from traditional diet, mainly composed of rice and vegetables, to Westernised diet rich, in meat and milk, along with the economic development and globalisation. Increasing prevalence of diet-related chronic diseases such as cancer and metabolic syndrome (MetS) is becoming a heavy burden to society and requires further attention. In this review, the association of meat and milk consumption with cancer and MetS among Koreans was discussed. Previous meta-analyses showed that meat intake was positively associated with increased risk of cancers, especially colon, as well as obesity and type 2 diabetes mellitus, and that the intake of milk and dairy products was negatively associated with colorectal cancer, obesity, and type 2 diabetes mellitus, based on studies conducted mostly in Western countries. In Korea and other Asian countries, the association of meat and milk intake with cancers were inconclusive and varied by types of cancers. Conversely, milk intake was negatively associated with MetS risk as reported in Western countries. The difference in results between Korea and Western countries might come from the differences in dietary patterns and study designs. Most Koreans still maintain traditional dietary pattern, although rapid change towards Westernised diet is underway among the younger age group. Randomised clinical trials or prospective cohort studies with consideration of combined effects of various dietary factors in Korea and other Asian countries are needed to elucidate the impact of meat and milk or related dietary patterns in their diet.

The objective of the present paper was to review the consumption status of meat and dairy products among Chinese residents. The research topics included production, consumption and health implications of dairy and meat, and the data sources included reports of national surveys, research papers and data from the National Bureau of Statistics of China. The average intake of meat, especially pork, has continued to increase in China. Pork intake increased from 37·1 g/d in 1992 to 64·3 g/d in 2012. There was a much higher margin in rural regions; pork intake of rural residents increased from 25·0 g/d in 1992 to 59·9 g/d in 2012, which resulted in a narrowed gap between urban and rural areas. Although the average intake of dairy products increased from 14·9 g/d in 1992 to 24·7 g/d in 2012, the overall level was still lower. There was a significant difference of dairy consumption between urban and rural residents. The gap of per capita consumption of milk between urban and rural households was 3·5 kg/year in 1990, reached the maximum of 16·9 kg/year in 2003, then decreased to 8·7 kg/year in 2012. In conclusion, the finding of this review sheds light on some problems with food consumption patterns in China. Effective strategies need to be adopted in order to change the consumption patterns. The consumption of milk and replacing pork with poultry or fish or other health foods should be encouraged.

In this overview of success stories in veterinary clinical nutrition topics in cats and dogs reviewed include the dietary management of chronic kidney disease, dissolution of urinary tract uroliths by dietary modification, the recognition that taurine and L-carnitine deficiencies can cause dilated cardiomyopathy; that clinical signs associated with feline hyperthyroidism (caused by a benign adenoma) can be controlled by a low-iodine diet alone; that dietary management of canine osteoarthritis can also reduce non-steroidal anti-inflammatory drug doses; and that disease-free intervals and survival times can be statistically longer in dogs with Stage III lymphoma managed with diet. As we discover more about nutrigenetics and nutrigenomics, and as we expand our basic understanding of idiopathic diseases we are bound to identify more nutritionally related causes, and be able to develop novel dietary strategies to manage disease processes, including the formulation of diets designed to alter gene expression to obtain beneficial clinical outcomes.

Obesity is arguably the biggest health and welfare issue affecting pet dogs. Although successful weight loss has health benefits, current strategies are far from ideal. Many obese dogs that start a weight programme fail to lose weight, or subsequently regain the weight they have lost. Given that current weight loss strategies are not perfect, clinicians need to focus carefully on tailoring the programme, perhaps setting a pragmatic target for weight loss, so as to ensure the benefits are maximised. This review will summarise key findings from recent clinical research into pet obesity, and present a framework for improving success, by better tailoring weight management regimens and end points to the individual.

Clinical deficiency of the B-vitamin riboflavin (vitamin B2) is largely confined to developing countries; however accumulating evidence indicates that suboptimal riboflavin status is a widespread problem across the developed world. Few international data are available on riboflavin status as measured by the functional biomarker, erythrocyte glutathione reductase activation coefficient, considered to be the gold standard index. One important role of riboflavin in the form of flavin dinucleotide is as a co-factor for the folate-metabolising enzyme methylenetetrahydrofolate reductase (MTHFR). Homozygosity for the common C677T polymorphism in MTHFR, affecting over 10 % of the UK and Irish populations and up to 32 % of other populations worldwide, has been associated with an increased risk of CVD, and more recently with hypertension. This review will explore available studies reporting riboflavin status worldwide, the interaction of riboflavin with the MTHFR C677T polymorphism and the potential role of riboflavin in personalised nutrition. Evidence is accumulating for a novel role of riboflavin as an important modulator of blood pressure (BP) specifically in individuals with the MTHFR 677TT genotype, with results from a number of recent randomised controlled trials demonstrating that riboflavin supplementation can significantly reduce systolic BP by 5–13 mmHg in these genetically at risk adults. Studies are however required to investigate the BP-lowering effect of riboflavin in different populations and in response to doses higher than 1·6 mg/d. Furthermore, work focusing on the translation of this research to health professionals and patients is also required.